Abstract
PAIgG from patients with ITP was evaluated by a competitive solid phase microenzyme immunoassay, and its specificity for anti-platelet antibody in patients with ITP was investigated by Western blotting. PAIgG values were elevated in most ITP patients whose platelet count was under 50, 000/μl, and within or close to normal range whose platelet count was over 50, 000/μl. Likewise PAIgG values elevated in ITP patients whose megakaryocyte count was over 200/μl, and within or close to normal range in most patients whose megakaryocyte count was normal. Following SDS-PAGE of whole platelet lysates or platelet membrane lysates, platelet fractions were transferred onto nitrocellulose strips by Western blotting. The binding immunoglobulin was detected with an avidin-biotin peroxidase system. Several bands of bound immunoglobulins were detect in the whole platelets lysates of all ITP patients, but most of the detectable bound immunoglobulins disappeared when platelet membrane lysate was used. This finding suggests that some immunoglobulins from ITP patients may bind to cytoplasmic proteins in the whole platelet lysate.
